Halacarus nitidus Bartsch 1979

Halacarus nitidus Bartsch, 1979

Halacarus nitidus: Bartsch (1979a: 179, figs 23–36).

Diagnosis. Length of male 375 µm. Epicuticula on plates and legs delicately striated. Frontal spine slender, medium-sized, its length 0.4 and 0.1 times that of AD and idiosoma, respectively. Posterior part of AD triangular, much wider than frontal spine. Pair of glp-1 at 0.6. Pair of ds-1 far posterior to glp-1, i.e. near end of AD, at 0.8 relative to length of plate and 0.6 relative to interval between glp-1 and posterior margin of AD. Ocular plates small, ovate, each with canaliculus in posterior margin. Pair of ds-5 medial to glp-4, removed from gland pores. Distance between glp-4 less than that between glp-5. Pair of ds-6 distinctly anteromedial to glp-5. Male with pair of small platelets in striated integument between ds-4 and ds-5. Male GA extending far between pair of PE. Anterior pair of pgs distinctly anterior to level of posterior seta of PE. GO in middle of male GA, surrounded by 70 pgs.

Gnathosoma 2.1 times longer than wide. Rostrum longer than gnathosomal base, extending almost to end of P- 3. Basal seta on P-2 at 0.6 relative to segment’s length. Legs longer than idiosoma. Trochanters I to IV with 1, 1, 2, 2 setae, basifemora I to IV with 2, 4, 2, 2 setae. Telofemur, genu and tibia I with 2, 2, 4 spiniform, tapering ventral setae. Basalmost ventral spine on telofemur I at 0.3. Ventromedial seta on genu II with delicate pectination (?), two ventromedial setae on tibia II bipectinate. Tarsi I to IV with 2, 1, 1, 1 ventral setae, tarsi III and IV with four and three dorsal setae, respectively. Paired claws of all tarsi with accessory process.

Remarks. An unique character of males is the pair of platelets between the ds-4 and ds-5. Males of H. discophorus have a similar pair of platelets between the ds-5 and ds-6, in females these platelets are lacking. The pair of ds-1 is in the posterior part of the AD, a character shared with H. perditus Newell, 1984. The two species differ in the arrangement of the ds-5 and ds-6 relative to glp-4 and glp-5, respectively.

Distribution and ecology. New Zealand, Auckland, Goat Island Bay, intertidal flat.